A combustion chamber comprises an upstream end wall, at least one annular wall, at least one fuel injector and at least one seal. The annular wall is secured to the upstream end wall and the upstream end wall has at least one aperture. Each fuel injector is arranged in a corresponding one of the apertures in the upstream end wall. Each seal is arranged in a corresponding one of the apertures in the upstream end wall and around the corresponding one of the fuel injectors. Each seal has a first portion, a second portion and a third portion. The second portion of each seal abuts the corresponding one of the fuel injectors. The third portion of each seal is arranged at the downstream end of the seal and the third portion increases in diameter in a downstream direction. The first portion of each seal is arranged upstream of the second portion and the first portion has a plurality of coolant apertures extending there-through.
The coolant apertures in the first portion of each seal direct the coolant there-through with axial and radial velocity components towards the third portion of the seal. The coolant impinges on the upstream surface, or cold surface, of the third portion of the seal to provide impingement cooling.
However, it has been realised that the impingement cooling of the upstream surface, or cold surface, of the third portion of the seal is not completely effective in reducing the temperature of the third portion of the seal sufficiently to prevent melting and melting back of the third portion of the seal. Melting of the third portion of the seal leads to material release and the realised material is deposited onto the annular wall of the combustion chamber, e.g. combustion chamber tiles, and other components of the gas turbine engine, e.g. turbine blades and turbine vanes, downstream of the combustion chamber. The deposition of molten material can lead to the blocking of cooling holes in the annular wall of the combustion chamber, e.g. the combustion chamber tiles, or blocking of cooling holes of components downstream of the combustion chamber. The blocking of the cooling holes in the annular wall of the combustion chamber, e.g. combustion chamber tiles, and other components downstream of the combustion chamber increases the temperature of these components and thereby reduces their working life. Furthermore, melting of the third portion of the seal also leads to a change in local mixing and stoichiometry in the combustion chamber resulting in an increase in the temperature of surrounding combustion chamber components, e.g. the combustion chamber heat shield and the burner seal locating rings. The increase of temperature of the surrounding combustion chamber components reduces the working life of these surrounding combustion chamber components.
The present disclosure seeks to produce a combustion chamber and a combustion chamber fuel injector seal which reduces, or overcomes, the above mentioned problem.